No one has attempted to bzip2 packages that might save space.
I remember a long discussion about time/space tradeoffs. bzip2 uncompression is a lot slower than gzip.
On newer computers (>1 GhZ) I think that the installation time is more determined by the speed of the I/O system than the speed of the CPU. bzip might actually help.
I believe that switching would increase the minimum memory requirements for Anaconda.
